New York Mets pitcher Edwin Diaz is expected to miss the entire MLB season after suffering a serious knee injury while celebrating a Puerto Rico win in the World Baseball Classic.

Diaz left the field in a wheelchair after injuring his right knee while celebrating Wednesday's win over the Dominican Republic, with his team-mates visibly upset by the incident.

On Thursday, the Mets revealed Diaz – who penned a five-year, $102million contract with the team in the offseason – had undergone surgery after sustaining a complete patellar tendon tear.

"Edwin Diaz underwent successful repair of the patellar tendon in his right knee today," read an update from the team. "He is expected to begin a formal rehab program in about a week."

Earlier on Thursday, Mets general manager Billy Eppler suggested the closer – widely considered to be the best in the game – could be sidelined for around eight months, a timeline which would rule him out for the entire 2023 season.

Eppler noted some athletes have returned from similar injuries within a six-month timeframe, but added such cases were "more the exception than the rule".

Diaz took to social media to update his fans after the surgery, writing on Twitter: "To all my beloved fans, especially the Mets fans, I want to let you know that I am doing well and healing.

"I feel blessed and grateful for your support with messages and prayers, thank you very much!  I can't wait to see you guys in NY again and play those trumpets."